THE  UNIVERSITY 

OF  ILLINOIS 

LIBRARY 

630.7 
116  b 


co 


A6RICULJURAL 
U1BW 


\ 


UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  NO.  244 


THE  FEED  COST  OF  MILK  AND  FAT 
PRODUCTION  AS  RELATED  TO  YIELDS 

BY  H.  A.  ROSS,  H.  F.  HALL,  AND  C.  S.  RHODE 


URBANA,  ILLINOIS,  MAY,  1923 


SUMMARY  OF  BULLETIN  No.  244 

This  bulletin  presents  a  method  of  comparing  the  feed  cost,  exclusive 
of  pasture,  of  milk  and  of  fat  production  for  cows  of  different  annual 
productions.  The  study  is  based  upon  data  obtained  from  cew-testing 
association  records  of  1,605  Holstein  cows  three  years  old  or  over,  which 
were  maintained  in  regions  where  milk  was  produced  almost  entirely  for 
fluid  consumption  or  for  condensing. 

When  these  records  were  divided  into  groups  on  the  basis  of  the 
amount  of  butter  fat  produced  in  one  'year,  the  average  production  of 
fat  for  the  groups  ranged  from  93  to  559  pounds,  with  an  average  of 
263  pounds  for  the  1,605  cows. 

The  consumption  of  concentrates  per  pound  of  fat  produced  was  found 
to  be  approximately  uniform  for  all  groups.  The  amounts  of  succulent 
and  dry  roughages  consumed  per  pound  of  fat  decreased  with  an  increase 
in  production. 

The  consumption  of  digestible  nutrients  per  pound  of  butter  fat  pro- 
duced and  the  annual  production  of  fat  per  cow  were  found  to  be  nega- 
tively correlated  (  —  0.4570  ±  .0133).  With  an  increase  in  production,  the 
nutrient  consumption  per  unit  of  product  decreased  at  an  ever-decreasing 
rate.  A  theoretical  curve  was  fitted  to  the  observed  data,  using  the 


formula  Y  =  '        +5.18  ;    in  which  Y  =   the   pounds   of   digestible 


nutrients  consumed  per  pound  of  fat  produced,  and  X  =  the  annual  pro- 
duction of  fat  in  pounds.  This  formula  was  used  as  a  basis  for  comparing 
the  feed  cost  of  fat  production  for  cows  of  various  annual  productions. 

When  current  values  were  applied  to  the  amounts  of  feed  consumed 
by  the  various  groups  of  cows,  it  was  found  that  the  cost  of  feed  per 
pound  of  digestible  nutrients  was  comparatively  uniform,  altho  slightly 
higher  for  the  highest-producing  cows.  The  maximum  variation  for  any 
one  year  of  the  fifteen-year  period,  1908-1922,  was  eleven-hundredths  of 
a  cent,  and  for  the  average  of  the  fifteen-year  period  it  was  only  six- 
hundredths  of  a  cent. 

When  the  1,605  records  were  divided  into  classes  based  on  the  amount 
of  milk  produced  annually,  the  average  prodxiction  for  the  various  groups 
was  found  to  range  from  3,081  pounds  to  16,711  pounds,  with  an  average 
for  all  the  cows  of  7,506  pounds. 

The  correlation  coefficient  —  0.4180  ±  .0139  indicates  the  relation  be- 
tween the  annual  yield  of  milk  and  the  nutrient  consumption  per  unit  of 

O/»C-|    r*r\ 

product.     This  relation  may  be  expressed  by  the  formula  Y  = 

A.  -f"  oO.YO 

+  14.95  ;  in  which  Y  =  the  nutrient  consumption  per  100  pounds  of  milk 
produced,  and  X  =  the  annual  production  of  milk  in  hundredweight. 

When  the  digestible  nutrients  in  the  feed  consumed  by  these  cows, 
exclusive  of  pasture,  was  compared  with  the  nutrient  requirement  as  com- 
puted by  the  Haeckcr  Standard,  it  was  found  that  for  the  majority  of 
the  cows  the  observed  consumption  was  approximately  65  percent  of  the 
theoretical  requirement,  indicating  that  35  percent  of  the  nutrients  may 
have  been  obtained  from  pasture. 


THE  FEED  COST  OF  MILK  AND  FAT 
PRODUCTION  AS  RELATED  TO  YIELDS 

BY  H.  A.  ROSS,  ASSOCIATE  IN  DAIRY  ECONOMY,  H.  F.  HALL,  FIRST  ASSISTANT  IN  DAIRY 
ECONOMY,  AND  C.  S.  RHODE,  ASSISTANT  PROFESSOR  OP  DAIRY  HUSBANDRY  EXTENSION 

That  high-producing  cows  require  less  feed  for  the  production  of 
a  given  quantity  of  milk  or  fat  tha,n  do  low-producing  cows  is  gen- 
erally recognized.  Upon  this  fact  rests  much  of  the  value  of  the 
work  of  cow -testing  associations.  These  associations  afford  a  practical 
means  of  determining -the  unprofitable  cows  which  may  well  be  elim- 
inated from  the  herd.  However,  only  a  small  percentage  of  the  dairy- 
men in  the  country  are  members  of  such  associations,  and  most  dairy- 
men, therefore,  must  rely  upon  some  other  means  of  determining  the 
profitableness  of  their  various  cows. 

Knowledge  of  the  amounts  of  milk  or  of  butter  fat  which  are 
produced  by  the  different  cows  in  a  herd  is,  of  course,  essential  to 
the  intelligent  culling  out  of  the  poor  cows ;  but  even  when  the  yield 
is  known,  the  problem  of  determining  the  minimum  production  which 
will  return  a  profit  still  remains.  Since  this  point  varies  with  the 
price  of  feed  and  labor  and  the  prices  of  dairy  products,  it  is  inadvis- 
able to  attempt  to  state  specifically  the  amount  of  milk  or  fat  which 
must  be  produced  annually  per  cow  in  order  to  obtain  a  profit.  It  is 
possible,  however,  to  compare  with  some  accuracy  the  cost  of  feed  for 
cows  of  one  level  of  production  with  the  cost  of  feed  for  cows  of  vari- 
ous other  levels  of  production.  This  study  aims  to  present  a  method 
whereby  such  comparisons  can  be  made  upon  other  than  a  ' '  dollar 
and  cents"  basis,  so  that  it  may  be  used  however  much  the  prices  of 
feeds  may  fluctuate. 

As  a  basis  for  comparing  the  amounts  of  feed  consumed,  the  total 
digestible  nutrients  in  the  feeds  are  used.  Necessarily  the  accuracy 
of  this  method  of  determining  relative  costs  depends  on  the  relative 
uniformity  for  all  groups  of  cows  of  the  cost  of  feed  per  pound  of 
digestible  nutrients.  The  extent  to  which  this  cost  varied  and  its 
effect  upon  the  accuracy  of  the  method  of  comparison  is  discussed 
later  (page  560). 

COMPARABLENESS  OF  RECORDS 

The  data  on  which  this  study  is  based  were  obtained  from  the 
records  of  fifteen  cow-testing  associations  in  Illinois.  They  were  col- 
lected by  the  associations  during  the  four-year  period  1917-1920.  The 

553 


554  BULLETIN  No.  244  [May, 

record  for  each  cow,  which  covered  a  period  of  one  year,  included  the 
following  data  for  each  month:  the  amount  of  milk  produced,  the 
percentage  of  fat  in  the  milk,  the  kind  and  quantity  of  feed  consumed, 
and  the  number  of  days  the  cow  was  pastured.  The  breed,  age,  and 
date  of  freshening  were  also  given.  The  estimated  weight  of  the 
cows  was  reported  in  approximately  one-half  of  the  records. 

Thousands  of  records  of  individual  cows  were  available  for  study, 
but  in  order  that  only  those  which  were  strictly  comparable  might  be 
used,  careful  selection  was  made  as  follows : 

1.  Records  were  considered  from  only  those  associations  which 
were  located  in  regions  where  milk  was  produced  for  fluid  consump- 
tion or  for  condensing.    By  thus  eliminating  the  herds  producing  for 
a  butter-fat  market,  a  fair  degree  of  uniformity  in  seasonal  production 
was  obtained  and  differences  in  the  rate  of  feeding  resulting  from 
price  stimulation  were  lessened. 

2.  From  these  associations,  fifteen  were  selected  because  of  the 
known  exceptional   ability   of  the   testers  in   charge  of   the  work. 
Eleven  of  these  fifteen  men  had  attended  agricultural  colleges  and  all 
of  them  were  noted  for  their  conscientious  attention  to  detail  in  test- 
ing milk  and  in  weighing  and  recording  the  feed  consumed.     Other 
associations  may  have  had  equally  able  testers,  but  by  taking  only 
those  of  known  ability  it  was  thought  that  the  accuracy  of  the  records 
would  be  assured. 

3.  All  records  were  discarded  which  were  in  any  way  incomplete. 
Among  these  were  records  of  cows  which  had  been  removed  from  test 
before  the  completion  of  the  year,  records  which  reported  the  value 
of  the  roughages  consumed  but  which  failed  to  state  the  amounts  in 
all  cases,  and  those  records  which  failed  to  give  the  breed  or  the  age 
of  the  cows. 

4.  Records  of  Holstein  cows  only  were  included  in  the  study  in 
order  to  limit  the  range  in  the  size  of  the  animals  and  in  the  percent- 
age of  fat  in  the  milk.    Approximately  19  percent  of  these  cows  were 
pure-breds. 

5.  Since  a  significant  proportion  of  the  feed  consumed  by  young 
cows  is  utilized  for  growth,  records  of  cows  under  three  years  of 
age  were  excluded  from  this  study. 

This  method  of  selection  left  1,605  records  which  were  deemed 
comparable.  Slight  differences  in  certain  factors,  such  as  the  seasonal 
production  and  the  percentage  of  fat  in  the  milk,  could  not  be  elim- 
inated, but  such  factors  have  been  included  in  the  tables  so  that  their 
effect  upon  the  feed  consumption  may  be  estimated. 


1983]  FEED  COST  OP  MILK  AND  FAT  PRODUCTION  555 

QUANTITY  OF  FEED  CONSUMED  AS  RELATED  TO 
FAT  PRODUCTION 

In  order  to  ascertain  the  relation  between  the  amount  of  fat  pro- 
duced per  cow  per  annum  and  the  quantity  of  feed  consumed,  the 
1,605  records  of  individual  cows  were  divided  into  groups  on  the 
basis  of  the  amount  of  the  fat  production.  The  average  fat  produc- 
tion per  cow  for  the  various  groups,  as  shown  by  Table  1,  ranged  from 
93  to  559  pounds,  with  a  mean  of  263  pounds  for  the  1,605  cows. 
Altho  a  wide  production  range  is  shown,  about  90  percent  of  all  the 
cows  fall  in  the  groups  producing  between  150  and  375  pounds  of 
butter  fat  annually  per  cow,  the  number  of  animals  in  the  groups 
producing  amounts  above  or  below  these  figures  being  very  small. 

The  average  fat  content  of  the  milk  of  these  cows  was  slightly 
higher  in  those  groups  of  greater  productivity,  the  percentage  rang- 
ing from  3.4  percent  to  3.7  percent  for  the  groups  having  sufficiently 
large  numbers  of  cows  to  give  comparable  averages.  Such  a  slight 
difference,  however,  probably  meant  very  little  difference  in  the 
amount  of  feed  consumed  and  may  therefore  be  ignored  in  comparing 
the  nutrient  consumption  of  the  different  groups  of  cows. 

The  variation  among  the  different  groups  in  regard  to  the  pro- 
portionate amounts  of  fat  produced  during  the  pasture  period  (May 
to  October)  are  shown  in  Table  1  in  the  form  of  percentages  of  the 
total  annual  production.  If  the  lowest-  and  highest-producing  groups 
having  very  few  records  are  omitted,  it  will  be  seen  that  the  propor- 
tion produced  during  the  pasture  period  decreases  as  the  annual  fat 
production  per  cow  increases.  This  means,  of  course,  that  the  lower- 
producing  groups  consumed  less  feed,  other  than  pasture,  than  would 
have  been  the  case  had  they  produced  as  large  a  proportion  of  fat 
in  the  winter  months  as  did  the  cows  of  higher  productivity.  The 
extent  to  which  this  seasonable  variation  in  production  may  have 
affected  the  feed  consumption  is  indeterminable. 

FEED  EXCLUSIVE  OF  PASTURE  THE  BASIS  OF  COMPARISON 

The  only  information  available  on  the  amount  of  feed  obtained 
from  pasture  by  these  cows  is  the  number  of  days  the  cows  were  pas- 
tured during  the  year.  These  figures  have  been  included  in  Table  1, 
altho  they  are  but  a  doubtful  indication  of  the  amount  of  nutrients 
consumed  because  of  the  extreme  variability  in  the  kind  and  quan- 
tity of  feed  afforded  the  different  animals  by  the  pastures.  It  should 
be  noted  that  the  number  of  days  the  cows  were  on  pasture  is  great- 
est for  the  lowest-producing  groups,  and  that  the  number  decreases 
with  the  groups  of  higher  production  up  to  the  group  producing 
from  200  to  225  pounds  of  fat  annually.  For  the  cows  producing 


556 


BULLETIN  No.  244 


[May, 


TABLE  1. — BUTTER  FAT  PRODUCTION  RECORDS  OF  1,605  HOLSTEIN  Cows  THREE 

YEARS  OLD  OR  OVER 


Group 
No. 

Annual 
production 
of  fat 
per  cow 

Number 
of  cows 

Average 
production 
of  fat 
per  cow 

Average 
fat  con- 
tent of 
milk 

Proportion 
of  fat  pro- 
duced during 
the  pasture 
period,  May 
to  October 

Average 
length  of 
time  cows 
were  on 
pasture 

1 

Ibs. 
75—100  .  . 

8 

Ibs. 
93 

percent 
3  3 

percent 
53 

days 
207 

2 

100—125  

17 

114 

3.3 

53 

218 

3 

125—150  

56 

138 

3.4 

59 

196 

4 

150  —  175  

94 

161 

3  4 

53 

190 

5 

175  —  200  

145 

188 

3  5 

48 

181 

6 

200—225  

171 

213 

3.5 

45 

176 

7 

225—250  

228 

237 

3.5 

46 

174 

8 

250  —  275  

217 

261 

3  5 

45 

175 

9 

275—300  

177 

287 

3  5 

42 

173 

10 

300—325  .  . 

172 

312 

3  6 

43 

173 

11 
12 
13 

325—350  
350—375  
375  —  400  

133 
90 
39 

337 
361 
386 

3.7 
3.6 
3.6 

41 
39 
40 

173 

169 
168 

14 

400  —  425  

26 

412 

3.7 

41 

176 

15 

425—450  

15 

435 

3.7 

39 

176 

16 

450—475  

9 

465 

3.7 

42 

156 

17 
18 

475—500  
500—525  

3 
2 

480 
517 

4.0 
•     4.0 

39 
35 

162 
153 

19 

525—550  

1 

526 

3.3 

38 

61 

20 

550—575  

2 

559 

3.5 

30 

153 

more  than  this  amount,  the  time  on  pasture  is  fairly  uniform.  There 
are  two  possible  explanations  of  this  relationship.  On  the  one  hand, 
if  the  somewhat  questionable  assumption  is  made  that  the  number 
of  days  on  pasture  is  an  index  of  the  total  nutrients  consumed  during 
that  time,  it  would  seem  that  the  poorer  cows  were  forced  to  obtain 
their  feed  from  pastures  after  the  better  cows  had  been  stabled  for 
the  winter.  On  the  other  hand,  the  longer  period  of  pasturing  may 
have  been  the  cause  of  the  lower  production  by  failing  to  furnish 
sufficient  feed  after  the  close  of  the  regular  pasture  season. 

Since  in  this  study  there  is  no  way  of  definitely  determining  the 
amount  of  nutrients  obtained  from  pastures,  only  the  feed  consumed 
other  than  pasture  is  considered  in  comparing  the  economy  of  the 
production  of  the  different  cows. 


AMOUNTS  OF  FEED  CONSUMED 

The  feed,  exclusive  of  pasture,  consumed  by  the  1,605  cows  has 
been  summarized  under  three  heads :  (1)  concentrates,  (2)  succulent 
roughage,  and  (3)  dry  roughage.  Table  2  shows  the  average  amounts 


19tS] 


FEED  COST  OF  MILK  AND  FAT  PRODUCTION 


557 


TABLE  2. — AVERAGE  AMOUNTS  OF  FEED  CONSUMED  IN  ONE  YEAR  BY  1,605 
HOLSTEIN  Cows  THREE  YEARS  OLD  OR  OVER:     EXCLUSIVE  OF  PASTURE 

As  related  to  fat  production 


Group 
No. 

Num- 
ber 
of 
cows 

Average 
production 
of  fat 
per  cow 

Feed  consumed 
per  cow 

Feed  consumed  per  pound 
of  fat  produced 

Con- 
cen- 
trates 

Succu- 
lent 
rough- 
age 

Dry 

rough- 
age 

Con- 
cen- 
trates 

Succu- 
lent 
rough- 
age 

Dry 

rough- 
age 

/6s. 

/6s. 

/6s. 

/6s. 

/6s. 

/6s. 

/6s. 

1 

8 

93 

688 

4  985 

1  534 

7.4 

53.6 

16.5 

2 

17 

114 

1  231 

5  198 

1  482 

10.8 

45.6 

13.0 

3 

56 

138 

883 

6  058 

1  628 

6.4 

43.9 

11.8 

4 

94 

161 

1  336 

6  408 

1  546 

8.3 

39.8 

9.6 

5 

145 

188 

1  391 

5  640 

1  918 

7.4 

30.0 

10.2 

6 

171 

213 

1  576 

6  326 

2  109 

7.4 

29.7 

9.9 

7 

228 

237 

1  754 

6  541 

2  086 

7.4 

27.6 

8.8 

8 

217 

261 

1  827 

6  629 

2  192 

7.0 

25.4 

8.4 

9 

177 

287 

2  038 

6  630 

2  353 

7.1 

23.1 

8.2 

10 

172 

312 

2  309 

6  302 

2  122 

7.4 

20.2 

6.8 

11 

133 

337 

2  292 

7  043 

2  258 

6.8 

20.9 

6.7 

12 

90 

361 

2  744 

6  823 

2  347 

7.6 

18.9 

6.5 

13 

39 

386 

2  856 

7  411 

2  277 

7.4 

19.2 

5.9 

14 

26 

412 

2  760 

7  004 

2  060 

6.7 

17.0 

5.0 

15 

15 

435 

2  784 

5  873 

2  219 

6.4* 

13.5 

5.1 

16 

9 

465 

3  534 

5  673 

2  464 

7.6 

12.2 

5.3 

17 

3 

480 

2  304 

8  880 

4  080 

4.8 

18.5 

8.5 

18 

2 

517 

3  877 

6  980 

1  810 

7.5 

13.5 

3.5 

19 

1 

526 

4  997 

11  835 

3  945 

9.5 

22.5 

7.5 

20 

2 

559 

4  472 

7  547 

1  677 

8.0 

13.5 

3.0 

of  these  classes  of  feeds  consumed  annually  per  cow  and  per  pound 
of  fat  for  the  various  production  groups. 

The  consumption  of  concentrates  bears  a  consistent  relation  to 
the  amount  of  fat  produced  by  the  cows  in  the  different  groups.  In 
other  words,  there  evidently  was  a  tendency  to  feed  the  cows  in  each 
herd  a  uniform  amount  of  grain  for  each  pound  of  fat  produced, 
regardless  of  the  individual  production  of  the  cows.  The  average 
amount  of  concentrates  consumed  per  pound  of  fat  for  all  the  cows 
whose  records  were  studied  is  7.3  pounds,  and  the  average  of  each 
group  varies  but  little  from  the  average  of  all,  except  in  those  groups 
having  only  a  few  cows. 

Succulent  roughage  consisted  almost  entirely  of  corn  silage,  altho 
small  amounts  of  green  corn,  beets,  and  wet  malt  were  included.  If 
the  groups  having  very  few  records  are  omitted,  it  will  be  seen  that  the 
succulent  roughage  was  consumed  in  amounts  ranging  from  approxi- 
mately 6,000  pounds  per  cow  in  the  lowest-producing  groups,  to  7,400 
pounds  per  cow  in  the  highest-producing  groups.  However,  the 
amount  of  succulent  roughage  consumed  per  pound  of  fat  produced 
decreases  rapidly  with  the  increase  in  production,  ranging  from  44 


558  BULLETIN  No.  244  [May, 

pounds  for  the  low-producing  cows  to  19  pounds  for  the  high- 
producing  cows.  Many  of  the  dairymen  managing  the  herds  from 
which  records  were  obtained  fed  each  cow  in  the  herd  the  same 
amount  of  silage,  while  others  varied  the  quantity  of  silage  somewhat 
but  not  in  proportion  to  the  production  of  milk  or  butter  fat. 

The  relation  between  dry  roughage  consumed  and  pounds  of  fat 
produced  is  similar  to  the  relation  between  silage  consumed  and  fat 
produced.  The  amount  of  dry  roughage  ranges  from  1,600  pounds  to 
2,300  pounds  per  cow,  or  from  approximately  12  to  6  pounds  per 
pound  of  fat. 

DIGESTIBLE  NUTRIENTS  IN  FEED  CONSUMED 

Three  facts  concerning  the  feed  consumption  of  these  cows  are 
apparent  from  the  data  in  Table  2.  These  are:  (1)  Approximately 
the  same  amount  of  concentrates,  per  pound  of  fat  produced,  was 
consumed  by  the  high-producing  cows  as  was  consumed  by  the  low- 
producing  cows.  (2)  The  amount  of  succulent  roughage  consumed, 
per  pound  of  fat  produced,  decreased  as  the  production  per  cow 
increased.  (3)  In  like  manner,  the  consumption  of  dry  roughage,  per 
pound  of  fat  prqduced,  decreased  with  the  increase  in  production. 
These  facts  indicate  that,  in  so  far  as  feed  consumption  is  concerned, 
high-producing  cows  are  more  economical  producers  of  fat  than  are 
low-producing  cows.  However,  if  a  quantitative  comparison  of  the 
groups  is  to  be  made,  it  is  necessary  to  reduce  the  three  classes  of  feed 
to  a  common  unit.  In  this  study,  total  digestible  nutrients  have  been 
selected  as  the  basis  of  comparison. 

Using  the  analyses  given  by  Henry  and  Morrison,1  the  amounts  of 
total  digestible  nutrients  in  the  feeds  consumed  by  each  cow  indi- 
vidually were  computed.  In  the  case  of  the  various  grains,  rough- 
ages, and  common  by-products,  these  values  were  applied  directly, 
but  for  certain  commercial  mixed  feeds  the  computation  of  the  amount 
of  digestible  nutrients  involved  some  estimates.  The  list  of  grains 
and  by-products  used  in  compounding  these  feeds  was  available,  but 
the  proportions  in  which  they  were  combined  were  not  known.  A 
formula  for  each  feed,  based  upon  the  list  of  ingredients  and  upon 
the  protein,  carbohydrate,  fat,  and  fiber  content  as  guaranteed  by 
the  manufacturer  was  therefore  assumed,  and  the  amount  of  digest- 
ible nutrients  in  the  mixed  feed  was  then  computed  upon  the  basis 
of  the  assumed  formula.  Such  a  method  was  considered  sufficiently 
accurate  for  a  study  of  this  kind,  and  it  is  probable  that  no  more  error 
is  involved  than  is  involved  in  the  assumption  of  uniform  quality  of 
the  grains  and  roughages  (which  is  made  when  average  values  are 
used  in  computing  the  digestible  nutrient  content).  The  amounts  of 
these  mixed  feeds  were  comparatively  small,  and  they  were  scattered 

'Feeds  and  Feeding.     15th  ed.  (1915),  pp.  653-666. 


19X3} 


FEED  COST  OF  MILK  AND  FAT  PRODUCTION 


559 


thruout  the  various  groups,  so  that  any  errors  involved  would  have 
practically  no  bearing  upon  the  relative  economy  of  the  fat  production 
of  the  various  groups. 

In  Table  3  are  shown  the  amounts  of  digestible  nutrients  in  the 
concentrates,  in  the  succulent  roughage,  in  the  dry  roughage,  and  in 
the  total  feed  consumed,  for  each  pound  of  fat  produced.  There  is 
a  significant  negative  correlation  ( — 0.4570  ±  .0133)  between  the 
annual  production  of  butter  fat  per  cow  and  the  nutrient  consump- 
tion per  pound  of  fat  produced.  The  total  digestible  nutrients  con- 
sumed per  pound  of  fat  produced  range  from  approximately  22 
pounds  in  the  two  lowest-producing  groups  to  10  pounds  in  the  groups 
with  the  highest  production.  The  decrease  in  the  consumption  of 
nutrients  per  pound  of  fat  produced,  with  the  increase  in  production 

2584.22 
per  cow,  is  expressed  by  the  formula,  Y  =  4-  5.18 ;    in 

which  Y  =  the  pounds  of  digestible  nutrients  consumed  per -pound 
of  fat  produced,  and  X=  the  total  production  of  fat  during  the 

TABLE  3. — DIGESTIBLE  NUTRIENTS  IN  FEED  CONSUMED  IN  ONE  YEAR  BY  1,605 

HOLSTEIN  Cows  THREE  YEARS  OLD  OR  OVER:    EXCLUSIVE  OF  PASTURE 

As  related  to  fat  production 


Group 
No. 

Num- 
ber 
of 
cows 

Average 
production 
of  fat 
per  cow 

Digestible  nutrients  consumed  per  pound  of 
fat  produced 

Concen- 
trates 

Succulent 
roughage 

Dry 
roughage 

All  feed 

Observed 

Computed1 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

1 

8 

93 

5.3 

9.4 

8.1 

22.8 

23.5 

2 

17 

114 

7.7 

8.1 

6.1 

21.9 

21.1 

3 

56 

138 

4.6 

7.9 

5.8 

18.3 

19.1 

4 

94 

161 

6.0 

7.0 

4.6 

17.6 

17.5 

5 

145 

188 

5.5 

5.3 

4.6 

15.4 

16.1 

6 

171 

213 

5.5 

52 

4.7 

15.4 

15.1 

7 

228 

237 

5.5 

4.8 

4.0 

14.3 

14.3 

8 

217 

261 

5.3 

4.5 

3.9 

13.7 

13.5 

9 

177 

287 

5.3 

4.1 

3.8 

13.2 

12.9 

10 

172 

312 

5.6 

3.6 

3.1 

12.3 

12.4 

11 

133 

337 

5.1 

3.6 

3.2 

11.9 

11.9 

12 

90 

361 

5.7 

3.4 

3.1 

12.2 

11.5 

13 

39 

386 

5.6 

3.3 

2.8 

11.7 

11.1 

14 

26 

412 

5.1 

2.9 

2.4 

10.4 

10.8 

15 

15 

435 

4.8 

2.4 

2.6 

9.8 

10.5 

16 

9 

465 

5.5 

2.1 

2.5 

10.1 

10.2 

17 

3 

480 

3.8 

33 

3.5 

10.6 

10  1 

18 

2 

517 

5.5 

2.3 

1.7 

9.5 

9.8 

19 

1 

526 

7.2 

4.1 

3.0 

14.3 

9.7 

20 

2 

559 

6.2 

2.5 

1.5 

10  2 

9.4 

'From  fitted  curve. 


.560 


BULLETIN  No.  244 


[May, 


year  in  pounds.1  As  shown  by  Fig.  1,  the  theoretical  curve  fits  closely 
the  actual  data  for  all  groups  except  Group  19,  which  includes  but 
one  animal.  Hence  it  may  be  concluded  that  within  the  limits  of  the 
production  range  shown  here,  the  amount  of  nutrients  consumed  per 
pound  of  fat  produced  decreases  at  an  ever-decreasing  rate  as  the 
production  per  cow  increases.  Stated  in  other  words,  the  curve  indi- 
cates that  as  a  dairyman  increases  the  potential  production  ability 
of  his  herd  he  decreases  the  feed  cost  of  producing  a  pound  of  fat ; 
and  furthermore,  this  decrease  is  more  rapid  in  going  from  a  very 
low  production  to  the  average,  than  it  is  in  going  from  the  average 
to  a  high  production. 


\ 


X 


ual  Proc/uctton  of  Fat  r>*r  Co*r 


FIG.  1. — THE  CONSUMPTION  OF  DIGESTIBLE  NUTRIENTS  AS  RELATED  TO 
FAT  PRODUCTION  (See  Table  3) 


The  high-producing  cows  in  this  study  consumed  a  greater  pro- 
portion of  concentrates  than  did  the  low-producing  cows;  and  since 
the  cost  of  concentrates  per  pound  of  nutrients  is  normally  higher 
than  the  cost  of  roughages,  it  might  appear  that  to  use  the  nutrient 
consumption  as  a  basis  of  comparing  feed  costs  would  involve  a  serious 
error.  This  would  be  particularly  true  if  the  records  of  cows  pro- 


1  The  formulas  used  in  this  study  were  derived  by  the  use  of  the  straight  line 
method.     Running,  Theodore  R.     Empirical  Formulas,  pp.  53-56,  1917. 


FEED  COST  OF  MILK  AND  FAT  PRODUCTION  561 

dueing  for  a  butter-fat  market  had  been  included  in  this  study,  be- 
cause the  majority  of  such  cows  produce  the  greater  part  of  their 
milk  on  pasture  and  are  fed  largely  on  cheap  roughages  during  the 
winter.  However,  as  was  stated  previously  (page  554),  the  records 
of  those  cows  only  which  were  producing  for  a  whole-milk,  or  year- 
round,  market  were  included  in  the  study.  Altho  these  cows  were 
not,  of  course,  all  managed  in  the  same  way,  the  variation  in  the  cost 
of  feed  per  pound  of  nutrients  was  less  than  would  have  been  the 
case  had  cows  in  butter-fat  regions  been  included. 

In  order  to  determine  the  variation  in  the  cost  of  the  rations  of 
these  cows,  the  amounts  of  the  various  kinds  of  feed  consumed  were 
tabulated  and  the  cost  of  feed  per  pound  of  digestible  nutrients  was 
computed  for  each  group  for  each  year  of  the  fifteen-year  period 
1908-1922.  The  computations  were  based  upon  the  current  values  of 
the  feeds  consumed.  Corn,  oats,  barley,  and  hay  were  figured  at  the 
average  of  Illinois  farm  values  for  each  month;  silage  was  valued 
at  its  hay  and  corn  equivalent.1  Bran,  cottonseed  meal,  linseed  oil 
meal,  middlings,  hominy  feed,  gluten  feed,  and  commercial  mixed 
feed  prices  were  figured  at  the  average  daily  Chicago  wholesale  prices, 
plus  sums  representing  the  cost  of  freight,  the  dealer's  profit,  and 
the  cost  of  hauling  the  feed  to  the  farm.2 

Table  4  shows  the  slight  variation  in  the  cost  of  nutrients  for  each 
of  the  nine  largest  groups  (Nos.  4  to  12).  The  other  groups  are 
omitted  because  the  number  of  cows  included  is  insufficient  to  give 
comparable  averages.  It  may  be  seen  from  this  table  that  even  dur- 
ing the  years  1917  to  1921,  when  the  cost  of  concentrates  was  rela- 
tively much  higher  than  the  cost  of  roughages,  the  greatest  difference 
in  the  cost  of  feed  for  any  two  groups  amounted  to  only  about  one- 
tenth  of  a  cent  per  pound  of  digestible  nutrients.  The  maximum 
variation  between  any  two  groups  in  the  average  cost  per  pound  of 
nutrients  for  the  entire  fifteen  years  was  only  six  hundredths  of  a 
cent.  In  other  words,  the  average  cost  of  feed  consumed  by  Group 
12,  per  pound  of  fat  produced,  is  found  to  be  21.0  cents  (11.5  X  1.83). 
If  the  cost  of  this  same  group  were  computed  on  the  basis  of  the 
cheapest  ration  (Group  6),  the  cost  per  pound  of  fat  would  be  20.4 
cents  (11.5  X  1-77),  a  difference  of  less  than  one  cent. 

It  should  be  pointed  out  that  the  cost  of  the  feeds  for  each  year 
was  computed  from  the  proportionate  amounts  of  the  various  kinds 
consumed  during  the  period  of  the  study,  1917  to  1920;  and  that 
these  proportions  might  have  been  somewhat  different  in  the  earlier 


1  Pearson,  F.  A.,  and  Gaines,  W.  L.  The  Evaluation  of  Corn  Silage,  (un- 
published data). 

"The  total  amounts  per  ton  added  to  the  wholesale  price  are  as  follows: 
1908  to  1915,  $4.50;  1916,  $5.50;  1917  and  1918,  $7.00;  1919,  $8.00;  1920. 
$8.50;  1921,  $7.00;  and  1922,  $6.00. 


562 


BULLETIN  No.  244 


[May, 


E 
P 

O 
K 

O 


s 


gfe  o 


O 

U 


fcg 

l|g& 

-^  «  *»  3 

OC     (N»  ^O  (^    ^   0J 

I-H  co  10  co  co 
"HOOOO 

(M  CO  CO  1^  t^ 

00000 

8 

S  oi 

1*= 

••§  s"  ™- 

[V]  Jrf   aj 

8?-°  £>E 

1|S& 

o  « 

ll 

«l| 

li  >-' 

Q)                  ^i 

s  I 

^2  »OTt<t^eo  (N 

jj   "^  'O  O  OS  !>• 

CO  l^.  CO  »  00 
•*  1C  »O  »O  CO 

COO*»O  CO  CO 
CO  •*  CO  CO  CO 

CO 
00 

.^3§ 

J  03  a 
£  S 

"O  3  O 

S    i-i  I-H  CO  (M  (N 

1—1 

§CQO 

•*->   bo 

a  S" 

a?    W3  T}H  ^  CO  1-1 
|j   •*  in  O  OS  t-- 

CO  »C  lO  O  O5 
T}<  1C  iC»CCO 

CO  •*  »C  1C  CO 
CO  rf  CO  CO  CO 

3 

O.4J   fl 
0  Jd-  = 

"11 

O    i-l  i-t  CO  CN  CN 

i-H 

°^S 

«4  O  09 

o     S 

>—  '      I3J 

Og     r-<  O  --H  O  1-H 

g    •*  >O  O  O5  t^ 

CO  ^  ^  ^  t^- 

•^  1C  1C  1C  CO 

»C  i-H  COCO  t-' 
CO  •*  COCO  CO 

§ 

Or^-- 

i^i 

:>sj 

S    i-l  i-H  CO  CNcN 

i-H 

Q«< 
v®% 

05      S 

CO    rH  i-l  00^02 

|J   T(<  IOO500CO 

00  <N  C<1  •*  CO 

CO  *O  »C  lO  00 

•*  ^H  COCO  CO 

co  -^  co  co  co 

s 

^^5 

-u^ 

a  «  S 
BJ3  0 

W    i-H  i-H  (N  (N  C<J 

i-H 

£vi 

"•OTH 

i—i 
00       CO 

<2  OO^H  osi>  ic 

^   CO  1C  O5  OO  ?D 

l^fMCOCOCO 
CO  «C  >C  1C  CO 

••*  <M  CO  O*  CO 

CO  "^  CO  CO  CO 

s 

TJ    02    S 

2  e.s 

111 

S    i-H  i-H  (M  N  <N 

i-H 

5  J  o 

°§"S 

t^.      cc 

eg    i-H  C^  OS  00  CO 
^   -^lOOiOOcO 

00<NC^Tj<  CO 
CO  »C  »O  >C  CO 

IO<M-*<NCO 
CO  •*  COCO  CO 

OS 

t^ 

03  0*S 

*Jfe 
•«5   >> 

2    i-H  i-H  <N  (N  W 

i-H 

§§^ 

aaQ 

cc" 

O        1-1 

og   OC<lt^U3CC 
^   •*  U5O5  00  CO 

ic  I-H  I-H  co  co 

CO  1C  >C  »C  CO 

-*  d  (MO5O 
CO-*  COIN  CO 

t^ 
t^. 

33^ 

"S-sl 

2  «  S 

S    ^H  i-H  C*  CM  C^ 

1-H 

_o  «  3 

•^'"^ 

00 

>C        QO 

«0     -H  fO  Q  t>-Tfl 

^    -^  lOOOOCO 

CO  ^H  T-H  CO  t^ 

CO  «C  tC«CCO 

•*  <N  (MO5O 

co  •*  COIN  co 

00 

t^ 

•  2««g 

>>S  <n 
2=«  01 
-C   O   O 

^^ 

^    ^H  T-H  CO  (M  M 

CS,^,-,^^ 

i-H 

•otS  a 

fl  °  - 

Tt*             S 

fiCCO-*  CO  00 
•<*  >O  O  OS  CO 

(M  CO  (M  1C  00 

rfi  1C  1C  *O  CO 

1C  •*  Tf  T-H  (N 

CO  -*  CO  CO  CO 

1—  1 
00 

03  a  e 
^^ 

^>-G    -t 

u  +s  ^ 

•^ 

«    i-H  ^HCO  <N<N 

*""* 

jiif 

-£  3^, 

aj   «  at 

°'Si's 

SUi 

«"«*:  S 

^A 

B      9 

&,""• 

^      *^ 

§  o  g^ 

"S  £ 

«*..  o 

5J 

0   S         0 

Oj    . 

§       '.''.''. 

a^  a 

•e  S  o  g 

o  t?  •** 

S    S3    M* 

_•  S  a 

0   rt  g 

hfl 

aj  a  o  "^ 

^  <u-^ 

c3 

^  «  .,  C 

Sc"S 

£Q    Sr" 

a*  § 

v 

trHM  J3fe 

8M 

<N  ^HOOJ  00 

b-  co  «c  •*  co 

M  ^H  O  O5  00 

> 
+t 

^TS 

t*  > 

o«u 

O)  O)  O)  O)  O) 

Oi  Oi  Ci  O5  O5 

Ci  Oi  G5  G2  G^ 

D§ 

19tS\ 


FEED  COST  OF  MILK  AND  FA.T  PRODUCTION 


563 


years  because  of  the  varying  prices  of  concentrates  and  roughages. 
It  would  appear,  however,  that  the  nutrient  basis  of  comparison  is 
sufficiently  accurate  for  the  practical  purposes  of  this  study. 

RELATIVE  FEED  COST  OF  BUTTER  FAT  PRODUCTION 

Since,  therefore,  the  cost  of  nutrients  in  the  rations  of  dairy  cows 
of  varying  fat  production,  appears  to  be  fairly  uniform,  the  feed 
cost  of  the  fat  produced  may  be  compared  by  the  use  of  the  preced- 
ing formula.  In  Table  5  are  presented  several  such  comparisons. 
The  relative  nutrient  consumption  indicates,  in  a  general  way,  the 
relative  feed  cost,  which  is  expressed  here  in  terms  of  percentages, 
the  nutrients  consumed  by  a  group  of  cows  with  an  average  produc- 
tion of  350  pounds  of  fat  being  used  as  a  base.  It  may  be  noted 
that  the  feed  cost  of  producing  a  pound  of  fat  is  twice  as  great  with 
cows  of  but  100  pounds  annual  production  as  it  is  with  cows  of  350 
pounds  annual  production.  Altho  it  is  evident  that  the  cost  of  feed 
for  any  one  cow  or  for  any  one  herd  of  cows  may  vary  widely  from 
the  average,  it  would  seem  that  these  data  show,  with  considerable 
accuracy,  the  relative  feed  cost  of  producing  fat  with  cows  of  various 
production  levels. 

TABLE  5. — RELATIVE  FEED  COST  OP  PRODUCING  ONE  POUND  OP  FAT  WITH  Cows 

OF  DIFFERENT  ANNUAL  PRODUCTIONS 
Based  upon  digestible  nutrient  consumption  exclusive  of  pasture 


Annual 
production 
of  fat 
per  cow 

'Digestible 
nutrients  consumed 
per  pound  of 
fat  produced 

Relative  feed 
cost  per 
pound  of 
fat  produced 

Ibs. 
350  

Ibs. 
11.67 

percent 
100 

325  

12  11 

104 

300  

12  60 

108 

275  

13.18 

113 

250  

13.85 

119 

225  

14.64 

125 

200  

15.60 

134 

175   

16.77 

144 

150  

18.23 

156 

125  

20.11 

172 

100  

22.63 

194 

'Computed  from  the  fitted  curve. 

QUANTITY  OF  FEED  CONSUMED  AS  RELATED 
TO  MILK  PRODUCTION 

In  order  to  determine  the  relative  feed  cost  of  the  milk  produced 
by  these  cows,  the  1,605  records  were  divided  into  groups  on  the 
basis  of  the  yearly  milk  production  per  cow.  The  average  production 
of  the  various  groups,  as  shown  by  Table  6,  ranged  from  3,081  pounds 


564 


BULLETIN  No.  244 


[May, 


to  16,711  pounds,  with  an  average  of  7,506.  When  the  cows  were 
grouped  on  this  basis,  the  average  percentage  of  fat  in  the  milk  pro- 
duced by  the  various  groups  was  found  to  decrease  slightly  with  the 
increase  in  production,  ranging  from  3.6  percent  to  3.3  percent  for 
the  groups  of  sufficient  size  to  be  considered.  Probably,  slightly  less 
feed  was  required  for  the  production  of  100  pounds  of  milk  with 
the  lower  fat  content  than  was  required  for  the  production  of  the 
higher  testing  milk.  However,  the  difference  in  the  amount  of  feed 
consumed  that  may  be  attributed  to  the  variation  in  the  fat  content 
of  the  milk  was  undoubtedly  less  than  the  difference  in  feed  consump- 
tion due  to  the  seasonal  variation  in  production.  The  higher- 
producing  cows  produced  a  greater  proportion  of  milk  during  the 
winter  months  than  did  the  lower-producing  cows.  This  means,  of 
course,  that  they  consumed  more  feed,  other  than  pasture,  than  they 
would  have  consumed  had  they  produced  the  same  proportion  of  milk 
during  the  winter  months  as  did  the  lower-producing  cows.  These 
two  factors  affecting  feed  consumption  (variation  in  fat  content  of 
milk  and  differences  in  seasonal  production)  cannot  be  eliminated,  but 
as  the  two  tend  to  counterbalance,  the  error  introduced  in  the  study 
is  thereby  lessened. 

TABLE  6. — MILK  PRODUCTION  RECORDS  OF  1,605  HOLSTEIN  Cows  THREE 
YEARS  OLD  OR  OVER 


Proportion 

Annual 

Average 

Average  fat 

of  milk  pro- 

Average 

Group 

production 

Number 

production 

content 

duced  during 

length  of 

No. 

of  milk 

of  cows 

of  milk 

of 

the  pasture 

time  cows 

per  cow 

per  cow 

milk 

period,  May 

were  on 

to  October 

pasture 

Ibs. 

Ibs. 

percent 

percent 

days 

1 

2  500—  3  500 

21 

3  081 

3.6 

49 

205 

2 

3  500—  4  500 

79 

4  094 

3.6 

57 

200 

3 

4  500—  5  500 

183 

5  065 

3.6 

50 

186 

4 

5  500—  6  500 

254 

6  032 

3.6 

46 

176 

5 

6  500—  7  500 

309 

7  013 

3.6 

45 

175 

6 

7  500—  8  500 

266 

7  972 

3.5 

43 

171 

7 

8  500—  9  500 

221 

.8  956 

3.5 

42 

170 

8 

9  500—10  500 

137 

9  938 

3.4 

41 

175 

9 

10  500—11  500 

76 

10  921 

3.4 

41 

163 

10 

11  500—12  500 

33 

11  943 

3.3 

39 

172 

11 

12  500—13  500 

19 

12  865 

3.3 

41 

155 

12 

13  500—14  500 

4 

13  710 

3.3 

38 

175 

13 

14  500—15  500 

1 

15  389 

3.4 

33 

152 

14 

15  500—16  500 

1 

15  825 

3.3 

38 

63 

15 

16  500—17  500 

1 

16  711 

3.4 

28 

152 

FEED  CONSUMED  AND  TOTAL  DIGESTIBLE  NUTRIENTS  IN  FEED 

Table  7  shows  the  amount  of  feed  consumed  both  per  cow  and  per 
100  pounds  of  milk  produced.  Practically  the  same  relation  obtains 
here  as  was  found  when  the  comparison  was  made  on  a  butter-fat 


19SS} 


FEED  COST  OF  MILK  AND  FAT  PRODUCTION 


565 


TABLE  7.— AVERAGE  AMOUNTS  or  FEED  CONSUMED  IN  ONE  YEAR  BY  1,605 
HOLSTEIN  Cows  THREE  YEARS  OLD  OR  OVER:     EXCLUSIVE  OF  PASTURE 

As  related  to  milk  production 


Feed  consumed 

Feed  consumed  per  100 

Num- 

Average 

per  cow 

pounds  of  milk  produced 

Group 
No. 

ber 
of 
cows 

production 
of  milk 
per  cow 

Con- 
cen- 
trates 

Succu- 
lent 
rough- 
age 

Dry 

rough- 
age 

Con- 
cen- 
trates 

Succu- 
lent 
rough- 
age 

Dry 

rough- 
age 

/6s. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

1 

21 

3  081 

746 

5  318 

1  500 

24.2 

172.6 

48.7 

2 

79 

4  094 

1  060 

5  764 

1  498 

25.9 

140.8 

36.6 

3 

183 

5  065 

1  352 

5  926 

1  783 

26.7 

117.0 

35.2 

4 

254 

6  032 

1  562 

6  279 

1  997 

25.9 

104.1 

33.1 

5 

309 

7  013 

1  767 

6  494 

2  167 

25.2 

92.6 

30.9 

6 

266 

7  972 

1  993 

6  744 

2  280 

25.0 

84.6 

28.6 

7 

221 

8  956 

2  230 

6  762 

2  311 

24.9 

75.5 

25.8 

8 

137 

9  938 

2  564 

6  748 

2  365 

25.8 

67.9 

23.8 

9 

76 

10  921 

2  829 

6  684 

2  184 

25.9 

61.2 

20.0 

10 

33 

11  943 

3  117 

6  139 

2  054 

26.1 

51.4 

17  2 

11 

19 

12  865 

3  769 

6  600 

2  522 

29.3 

51.3 

19.6 

12 

4 

13  710 

2  989 

4  456 

2  399 

21.8 

32.5 

17.5 

13 

1 

15  389 

4  386 

8  464 

1  924 

28.5 

55.0 

12.5 

14 

1 

15  825 

4  985 

11  869 

3  561 

31.5 

75.0 

22.5 

15 

1 

16  711 

4  261 

5  849 

2  089 

25.5 

35.0 

12.5 

TABLE  8. — DIGESTIBLE  NUTRIENTS  IN  FEED  CONSUMED  IN  ONE  YEAR  BY  1,605 
HOLSTEIN  Cows  THREE  YEARS  OLD  OR  OVER:     EXCLUSIVE  OF  PASTURE 

As  related  to  milk  production 


Group 
No. 

Num- 
ber 
of 
cows 

Average 
production 
of  milk 
per  cow 

Digestible  nutrients  consumed  per  100  pounds 
of  milk  produced 

Concen- 
trates 

Succulent 
roughage 

Dry 

roughage 

All  feed 

Observed 

Computed1 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

fas. 

Ibs. 

1 

21 

3  081 

17.1 

30.1 

23.7 

70.9 

69.0 

2 

79 

4  094 

18.3 

25.5 

17.6 

61.4 

62.0 

3 

183 

5  065 

19.2 

20.6 

16.5 

56.3 

56.7 

4 

254 

6  032 

19.1 

18.5 

15.5 

53.1 

52.6 

5 

309 

7  013 

18.6 

16.6 

14.5 

49.7 

49.1 

6 

266 

7  972 

18.8 

•    15.0 

13.2 

47.0 

46.3 

7 

221 

8  956 

19.0 

13.4 

11.9 

44.3 

43.9 

8 

137 

9  938 

19.3 

12.0 

10.8 

42.1 

41.8 

9 

76 

10  921 

19.6 

10.8 

9.7 

40.1 

40.0 

10 

33 

11  943 

19.7 

9.0 

8.3 

37.0 

38.3 

11 

19 

12  865 

22.5 

8.8 

9.2 

40.5 

37.0 

12 

4 

13  710 

15.8 

6.0 

7.5 

29.3 

36.0 

13 

1 

15  389 

23.9 

10.0 

5.3 

39.2 

34.1 

14 

1 

15  825 

22.5 

13.5 

10.5 

46.5 

33.7 

15 

1 

16  711 

19.5 

7.5 

4.5 

31.5 

32.9 

'From  fitted  curve. 


566 


BULLETIN  No.  244 


[May, 


basis.  The  amount  of  concentrates  consumed  per  100  pounds  of 
milk  produced  is  approximately  constant  for  all  groups,  while  the 
amounts  of  succulent  and  dry  roughages  per  unit  of  product  decrease 
as  the  production  increases. 

The  tetal  digestible  nutrients  in  the  feed  consumed  per  100  pounds 
of  milk  produced  (Table  8)  decrease  at  an  ever-decreasing  rate  with 
the  increase  in  production,  in  a  manner  similar  to  the  decrease  in 
nutrients  with  the  increase  in  fat  production  (Table  3  and  Fig.  1). 
The  correlation  between  milk  production  and  nutrient  consumption 
per  hundredweight  of  milk  is  — 0.4180  ±  .0139,  as  compared  with  the 
fat  production  and  nutrient  consumption  correlation  of  — 0.4570 
±  .0133.  The  fitted  curve  shown  in  Fig.  2  is  expressed  by  the 

formula  Y  =  '        -4-  14.95 ;    in  which  Y=  the  pounds  of  di- 

.A.  -j—  OO.ID 

gestible  nutrients  consumed  per  100  pounds  of  milk  produced,  and 
X  =  the  annual  production  of  milk  in  hundredweight. 

The  relative  feed  cost  of  producing  milk  with  cows  of  different 
annual  productions  may  be  computed  by  the  use  of  this  formula  in 
the  same  way  that  the  relative  feed  cost  of  fat  production  was  com- 
puted. Table  9  shows  such  a  comparison,  the  nutrients  consumed  by 
cows  producing  10,000  pounds  annually  being  used  as  a  base.  Any 
other  production  would  serve  equally  well  as  a  basis  of  comparison; 
the  one  used  is  selected  merely  for  illustration.  In  this  case  the  cost 
of  feed  per  100  pounds  of  milk  was  67  percent  greater  for  the  3000- 
pound  cows  than  for  the  10,000  pound  cows. 


I 

i 

I 

I 

I 

Q     ,0 


\ 


Annual  Praducf/on  of  Milk  p*r  Co* 


FIG.  2. — THE  CONSUMPTION  OF  DIGESTIBLE  NUTRIENTS  AS  BELATED 
TO  MILK  PRODUCTION  (See  Table  8) 


FEED  COST  OF  MILK  AJCD  FAT  PRODUCTION 


567 


TABLE  9. — RELATIVE  FEED  COST  OF  PRODUCING  100  POUNDS  OF  MILK  WITH  Cows 
OF  DIFFERENT  ANNUAL  PRODUCTIONS 

Based  upon  digestible  nutrient  consumption  exclusive  of  pasture 


Annual 
production 
of  milk 
per  cow 

Digestible 
nutrients  consumed 
per  100  pounds  of 
milk  produced 

Relative  feed 
cost  per  100 
pounds  of 
milk  produced 

Ibs. 
10  000  

Ibs. 
41.7 

percent 
100 

9  000  

43  8 

105 

8  000  

46.2 

111 

7  000  

49.2 

118 

6  000  

52.7 

126 

5  000  

57.0 

137 

4  000  

62  5 

150 

3  000  

69.7 

167 

'Computed  from  the  fitted  curve. 

NUTRIENTS  OBTAINED  FROM  PASTURE 

Altho  the  data  in  this  study  do  not  include  figures  on  the  amount 
of  nutrients  obtained  from  pasture,  these  figures  may  be  computed  by 
an  indirect  method.  Such  a  method  involves  the  assumption  that  the 
difference  between  the  observed  nutrient  consumption  of  these  cows 
and  the  nutrient  requirement  as  computed  by  a  feeding  standard 
represents  the  nutrients  obtained  from  pasture.  This  is,  of  course, 
rather  a  broad  assumption;  but  in  view  of  the  lack  of  information 
concerning  the  proportion  of  feed  that  is  obtained  from  pasture  under 
practical  farm  conditions,  it  seems  worth  while  to  present  these  data 
for  whatever  they  are  worth. 

The  digestible  nutrient  requirement  per  100  pounds  of  milk  was 
computed  according  to  the  Haecker  Feeding  Standard,3  account  being 
taken  of  the  weights  of  these  cows  and  of  the  fat  content  of  the  milk. 
From  this  computed  requirement  were  deducted  the  nutrients  in  the 
feed  consumed  exclusive  of  pasture,  which  are  given  in  Table  8.  The 
result  is  the  computed  amount  of  nutrients  obtained  from  pasture. 
Table  10  and  Fig.  3  show  that  the  low-producing  cows  obtained  a 
much  greater  proportion  of  their  feed  from  pasture  than  did  the 
high-producing  cows.  This  conclusion  is  supported  by  the  fact  that 
the  low-producing  cows  were  on  pasture  a  longer  time  and  produced 
a  relatively  greater  proportion  of  the  milk  during  the  pasture  period 
(Table  11). 

These  data  indicate  that  a  surprisingly  high  percentage  of  the  total 
nutrients  consumed  were  obtained  from  pasture.  If  such  a  comparison 
of  the  feeding  standard  requirement  and  the  observed  nutrient  con- 
sumption is  valid,  each  of  the  groups  of  cows  obtained  over  one-third 
of  the  feed  from  this  source,  altho,  for  most  of  the  groups,  less  than 


See  reference  bearing  this  number,  page  573. 


568 


BULLETIN  No.  244 


[May; 


45  percent  of  the  total  year's  production  came  in  the  pasture  period 
from  May  to  October. 


TABLE  10. — COMPARISON  OP  THE  AMOUNT  OF  NUTRIENTS  REQUIRED  TO  PRODUCE 
100  POUNDS  OF  MILK   AS  COMPUTED  BY  THE   HAECKER  FEEDING 
STANDARD,  AND  THE  OBSERVED  NUTRIENT  CONSUMPTION 
EXCLUSIVE  OF  PASTURE 


Total  digestible  nutrients  in  feed 

consumed  per  100  pounds  of 

milk  produced 

Group 
No. 

Average 
produc- 
tion of 

'Weight 
of 

Age 
of 

Average 
fat 
content 

Required 
by  the 
Haecker 

'Consumed 
by  the 
1,605 

Difference 
between 
feeding 
standard 

milk 
per  cow 

cows 

cows 

of  milk 

Feeding 
Standard 

cows  in 
this  study 
(pasture 
excluded) 

require- 
ment and 
observed 
consumption 

Ibs. 

Ibs. 

yrs. 

percent 

Ibs. 

Ibs. 

Ibs. 

1 

3  081 

968 

6.0 

3.6 

122.2 

69.0 

53.2 

2 

4  094 

993 

5.0 

3.6 

101.5 

62.0 

39.5 

•  3 

5  065 

1  018 

5.1 

3.6 

89.4 

56.7 

32.7 

4 

6  032 

1  042 

5.7 

3.6 

81.3 

52.6 

28.7 

5 

7  013 

1  066 

5.9 

3.6 

75.3 

49.1 

26.2 

6 

7  972 

1  090 

6.1 

3.5 

70.6 

46.3 

24.3 

7 

8  956 

1  115 

6.2 

3.5 

67.0 

43.9 

23.1 

8 

9.938 

1  139 

6.5 

3.4 

63.1 

41.8 

21.3 

9 

10  921 

1  164 

6.6 

3.4 

60.7 

40.0 

20.7 

10 

11  943 

1  190 

7.0 

3.3 

58.7 

38.3 

20.4 

11 

12  865 

1  216 

6  4 

3.3 

57.2 

37.0 

20.2 

12 

13  710 

1  232 

7.0 

3.3 

55.9 

36.0 

19.9 

13 

15  389 

1  276 

7.5 

3.42 

53.9 

34.1 

19.8 

14 

15  825 

1  287 

4.5 

3.3 

53.4 

33.7 

19.7 

15 

16  711 

1  309 

7.5 

3.42 

52.6 

32.9 

19.7 

'Approximately  half  the  records  give  the  weights  of  the  cows,  and  the  esti- 
mated weights  presented  in  this  table  are  based  upon  the  averages  of  these  records. 

2Groups  13  and  15  include  but  one  cow  each,  and  in  computing  the  nutrient 
requirement  by  the  use  of  the  Haecker  Standard,  a  uniform  test  of  3.3  percent  has 
been  used  for  these  two  groups. 

3Computed  from  the  fitted  curve. 


1983] 


FEED  COST  OF  MILK  AND  FAT  PRODUCTION 


569 


FIG.  3. — AMOUNT  OF  NUTRIENTS  REQUIRED  TO  PRODUCE  100  POUNDS  OF  MILK,  AS 

COMPUTED  BY  THE  HAECKER  FEEDING  STANDARD  AND  THE  OBSERVED 

NUTRIENT  CONSUMPTION  EXCLUSIVE  OF  PASTURE 

Tho  the  difference  between  the  observed  nutrient  consumption  and  the  theo- 
retical requirement  based  on  Haecker's  Standard  may  not  be  an  exact  measure- 
ment of  the  amount  of  nutrients  obtained  from  pasture,  it  may  be  taken  as  a 
rough  approximation. 


570 


BULLETIN  No.  244 


[May, 


TABLE  11. — COMPARISON  OF  THE  PROPORTION  OF  MILK  PRODUCED  DURING  THH 
PASTURE  PERIOD,  THE  LENGTH  OF  TIME  THE  Cows  WERE  ON  PASTURE, 
AND  THE  COMPUTED  PROPORTION  OF  NUTRIENTS  OBTAINED 
FROM  PASTURE 


Group 
No. 

Production 
of  milk 
per  cow 

Proportion  of 
milk  produced 
during  the  pasture 
period,  May 
to  October 

Average  length 
of  time  cows 
were  on  pasture 

'Computed  propor- 
tion of  total  nutrients 
consumed  during  the 
year,  obtained 
from  pasture 

Ibs. 

percent 

days 

percent 

1 

3  081 

49 

205 

43.5 

2 

4  094 

57 

200 

38.9 

3 

5  065 

50 

186 

36.6 

4 

6  032 

46 

176 

35.3 

5 

7  013 

45 

175 

34.8 

6 

7  972 

43 

171 

34.4 

7 

8  956 

42 

170 

34.5 

8 

9  938 

41 

175 

33.8 

9 

10  921 

41 

163 

34.1 

10 

11  943 

39 

172 

34.8 

11 

12  865 

41 

155 

35.3 

12 

13  710 

38 

175 

35.6 

13 

15  389 

33 

152 

36.7 

14 

15  825 

38 

63 

36.9 

15 

16  711 

28 

152 

37.5 

difference  between  the  nutrient  requirement  per  100  pounds  of  milk, 
as  computed  by  the  Haecker  Standard,  and  the  observed  consumption  is  assumed 
to  represent  the  nutrients  obtained  from  pasture. 

FORCED  FEEDING  FOE  MAXIMUM  YIELDS  AND 
FEED  COST  OF  PRODUCTION 

In  order  to  avoid  possible  misinterpretation  in  the  application  of 
these  data  on  the  relative  feed  cost  of  milk  and  fat  production,  it 
should  perhaps  be  stated  that  the  study  does  not  show  that  the  most 
economical  production  is  obtained  by  feeding  for  maximum  produc- 
tion. It  does  show  that  cows  of  inherently  high  production  ability  are 
more  economical  producers  than  cows  of  low  production  ability.  A 
clear  distinction  should  be  made  between  these  two  factors  (rate  of 
feeding  and  inherent  production  ability)  which  tend  to  determine 
yield,  because  the  economy  of  production  is  quite  different  in  the 
two  cases. 

If  a  cow  is  given  increasing  amounts  of  feed,  a  point  is  eventually 
reached  where  the  increased  milk  flow  is  not  proportional  to  the  in- 
crease in  feed.  In  feeding  for  maximum  production,  this  point  of 
greatest  efficiency  is  passed,  and  the  feed  consumed  per  unit  of 
product  is  usually  greater  than  it  would  have  been  had  the  cow  been 
fed  a  somewhat  lighter  ration.  This  is  well  illustrated  by  Holtsmark  's 
work  based  on  846  dairy  herds  in  Norway.4  Table  12,  taken  from 


*  See  reference  bearing  this  number,  page  573. 


1.9MJ 


FEED  COST  OP  MILK  AND  FAT  PRODUCTION 


571 


his  study,  shows  that  the  yield  of  milk  for  each  100  feed  units  in- 
creases up  to  the  third  group,  which  received  2,500  feed  units.  This 
represents  the  point  of  greatest  efficiency ;  the  groups  of  cows  which 
were  fed  more  than  this  amount  showed  decreasing  yields  of  milk  for 
each  100  feed  units  consumed. 

TABLE  12. — RELATION  BETWEEN  THE  AMOUNT  OF  FEED  CONSUMED  AND  THE 
MILK  PRODUCED  BY  846  DAIRY  HERDS  IN  NORWAY 
According  to  Holtsmark 


Number  of  feed 
units  consumed 
per  cow 

Yield  of 
milk 
per  cow 

Yield  of  milk 
per  100 
feed  units 

1  500.. 

kilograms 
923 

kilograms 
61.5 

2  000  

1  424 

71.2 

2  500.  

1  813 

72  5 

3  000  

2  131 

71.0 

3  500  

2  399 

68.5 

4  000  

2  632 

65.8 

4  500  

2  837 

63.1 

In  contrast  to  feeding  for  maximum  production  is  the  building  up 
of  a  herd  of  cows  with  the  idea  of  increasing  their  potential  produc- 
tion ability.  As  the  herd  is  improved  and1  the  production  per  cow 
increased,  the  relative  amount  of  feed  required  for  maintenance  be- 
comes smaller  and  smaller  and  the  feed  consumed  per  unit  of  product 
continues  to  decrease,  altho  at  a  very  slow  rate  for  high-producing 
cows.  Stated  in  other  words,  in  so  far  as  the  feed  cost  of  milk  and 
fat  production  is  concerned,  feeding  for  maximum  production  is  sub- 
ject to  the  economic  law  of  increasing  costs,  while  increasing  the 
potential  ability  for  high  production  is  subject  to  the  law  of  de- 
creasing costs. 

The  cows  included  in  this  study  were  cared  for  by  practical 
farmers  producing  milk  for  profit.  It  may  be  assumed  that,  with  the 
exception  of  a  few  animals  which  were  on  official  test,  these  cows  were 
fed  with  the  idea  of  producing  a  large  amount  of  milk  as  economically 
as  possible.  This  does  not  mean  that  each  farmer  fed  to  the  point  of 
greatest  economic  efficiency  but,  since  high-  and  low-producing  cows 
were  found  in  the  same  herds,  it  is  probable  that  the  means  of  the 
larger  groups  represent  cows  fed  to  approximately  the  same  point  as 
regards  efficiency  in  the  utilization  of  feed.  It  is  quite  possible  that 
the  lowest-producing  cows  may  have  been  underfed  and  the  extremely 
high-producing  groups,  overfed.  In  general,  however,  the  variation 
in  the  production  of  the  cows  studied  appears  to  have  been  due  to  the 
inherent  differences  in  production  ability  rather  than  to  differences 
in  feeding.  The  data  in  Tables  5  and  9  may  therefore  be  taken  as  rep- 
resenting approximately  the  relative  economy  of  fat  and  milk  produc- 
tion by  high-  and  by  low-producing  cows. 


572  BULLETIN  No.  244  [May, 

CONCLUSIONS 

From  this  study  of  1,605  Holstein  cows,  three  years  old  or  over, 
it  may  be  concluded  that  the  annual  production  of  milk  and  fat  per 
cow  and  the  nutrient  consumption  per  unit  of  product  are  negatively 
correlated.  As  production  is  increased  by  increasing  the  potential 
production  ability  of  a  herd,  the  amount  of  nutrients  consumed  per 
unit  of  product  decreases  at  an  ever-decreasing  rate.  This  relation 
is  expressed  by  hyperbolic  curves.  As  long  as  the  cost  of  nutrients 
in  the  rations  of  dairy  cows  is  fairly  uniform,  these  curves  may  be 
used  to  compare  the  relative  feed  cost,  exclusive  of  pasture,  of  milk 
and  fat  production  for  cows  similar  to  those  studied  if  they  are  fed 
and  cared  for  in  a  like  manner. 

If  it  is  assumed  that  the  difference  between  the  amount  of 
nutrients  required,  as  given  by  the  Haecker  Standard,  and  the 
amount  consumed  by  these  cows  in  concentrates,  succulent  roughage, 
and  dry  roughage,  represents  the  nutrients  obtained  from  pasture,  it 
would  appear  that  the  majority  of  these  cows  obtained  from  pasture 
approximately  35  percent  of  the  total  nutrients  consumed. 


1923]  FEED  COST  OF  MILK  AND  FAT  PRODUCTION  573 


BIBLIOGRAPHY 

1.  BRONSON,  W.  H.    The  cost  of  milk  production  in  Massachusetts.     Mass.  Agr. 
Col.  Ext.  Serv.  Bui.  19.     1918. 

2.  COOPER,  MORTON  O.,  BENNETT,  C.  M.,  and  CHURCH,  L.  M.     A  study  in  the 
cost  of  producing  milk  on  four 'dairy  farms,  located  in  Wisconsin,  Michigan, 
Pennsylvania,  and  North  Carolina.     U.  S.  Dept.  Agr.  Bui.  501.     1917. 

3.  HAECKER,  T.  L.     Investigations  in  milk  production.     Minn.  Agr.  Exp.  Sta. 
Bui.  140.    1914. 

4.  HOLTSMARK,  G.     Om   Forholdet   Mellem   Melkeudbytte   og  Anvcndt   Foder. 
Arch.  Math,  og  Naturvid.,  26,  2,  1-17.     1905. 

5.  HOPPER,  H.  A.,  and  EOBERTSON,  F.  E.     The  cost  of  milk  production.     N.  Y. 
(Cornell)  Agr.  Exp.  Sta.  Bui.  357.     1915. 

6.  HOPPER,  H.  A.,  BOWEN,  H.  M.,  and  BARLOW,  F.  S.     Feed  consumed  in  milk 
production.     N.  Y.   (Cornell)  Agr.  Exp.  Sta.  Bui.  398.     1918. 

7.  MCDOWELL,  J.  C.    Relation  of  production  to  income  from  dairy  cows.     U.  S. 
Dept.  Agr.  Bui.  1069.     1922. 

8.    .     Influence  of  season  of  freshening  on  production  and  income 

from  dairy  cows.    U.  S.  Dept.  Agr.  Bui.  1071.    1922. 

9.  MENDUM,  S.  W.     Cost  of  milk  production  on  forty-eight  Wisconsin  farms. 
U.  S.  Dept.  Agr.  Bui.  1144.    1923. 

10.  MUSSER,  K.  B.,  WHITE,  G.  C.,  MCDONALD,  B.  A.,  and  JUDKINS,  H.  F.    Studies 
from  the  survey  on  the  cost  of  market  milk  production.     Conn.  Agr.  Col. 
Ext.  Serv.  Bui.  7.    1917. 

11.  RASMUSSEN,  F.     Cost  of  milk  production.     N.  H.  Col.  and  Sta.  Ext.  Bui.  2. 
1913. 

12.  THOMPSON,  A.  L.    Cost  of  producing  milk  on  174  farms  in  Delaware  county, 
New  York.     N.  Y.  (Cornell)  Agr.  Exp.  Sta.  Bui.  364.     1915. 

13.  WING,  H.  H.     Cost  of  milk  production,  variation  in  individual  cows.     N.  Y. 
(Cornell)  Agr.  Exp.  Sta.  Bui.  52.     1893. 

14.  WOLL,  F.  W.     The  feed  unit  system  for  determining  the  economy  of  pro- 
duction by  dairy  cows.    Wis.  Agr.  Exp.  Sta.  Circ.  37.     1912. 

15.  WOLL,  F.  W.,  and  HARRIS,  R.  T.    The  Wisconsin  dairv  cow  competition.   Wis. 
Agr.  Exp.  Sta.  Bui.  226.     1912. 


UNIVERSITY  OF  ILLINOIS-URBANA 


